<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>DOM操作CSS</title>

    <style>
        #div{
            width: 500px;
            height: 500px;
            background-color: seagreen;
        }


    </style>
</head>
<body>
    <div id="div"></div>
    <button id="btn">提交</button>

    <script>
        let btn =document.getElementById("btn");
        let div =document.getElementById("div");

        btn.onclick =function(){
            div.style.width = "1000px";
            div.style.height = "1000px";
            div.style.backgroundColor =red;

        }
    </script>
</body>
</html>